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Elbow Joint: Anatomy

The elbow is the synovial hinge joint between the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy in the upper arm Arm The arm, or "upper arm" in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy and the radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy and ulna Ulna The inner and longer bone of the forearm. Forearm: Anatomy in the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term "forearm" is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy. The elbow consists of 3 joints, which form a functional unit enclosed within a single articular capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides. The elbow is the link between the powerful motions of the shoulder and the intricate fine-motor function of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy. To provide that link, the motions of the elbow include extension Extension Examination of the Upper Limbs and flexion Flexion Examination of the Upper Limbs as well as pronation Pronation Applies to movements of the forearm in turning the palm backward or downward. When referring to the foot, a combination of eversion and abduction movements in the tarsal and metatarsal joints (turning the foot up and in toward the midline of the body). Examination of the Upper Limbs and supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term "forearm" is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy.

Last updated: Mar 9, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Parts of the Elbow Joint

The elbow joint consists of 3 separate articulations enclosed in a single capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides:

Joint Articular surfaces Type Function
Humeroulnar joint Simple hinge-joint
  • Flexion-extension
  • Circumduction
Humeroradial joint Limited ball-and-socket joint Limited pronation-supination in semiflexion
Proximal radioulnar joint Proximal radioulnar joint Forearm: Anatomy
  • Head of the radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy
  • Radial notch of the ulna Ulna The inner and longer bone of the forearm. Forearm: Anatomy
Pivot joint Pronation-supination in any degree of flexion-extension

Ligaments of the Elbow Joint

The elbow capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides is supported by the ligaments of the elbow, especially the radial (lateral) and ulnar (medial) collateral ligaments.

Ligament Attachments Function
Radial collateral ligament Stabilizes the elbow joint against varus stress
Ulnar collateral ligament Stabilizes the humeroulnar joint against valgus stress
Annular Annular Dermatologic Examination ligament of the radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy Anterior-posterior margins of the radial notch Surrounds and anchors the radial head to the radial notch of the ulna Ulna The inner and longer bone of the forearm. Forearm: Anatomy
Interosseous membrane Interosseous Membrane A sheet of fibrous connective tissue rich in collagen often linking two parallel bony structures forming a syndesmosis type joint. It provides longitudinal stability, tensile strength, and weight distribution/transfer and may allow limited movement in syndesmoses. Forearm: Anatomy Interosseous margins of the radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy and the ulna Ulna The inner and longer bone of the forearm. Forearm: Anatomy
  • Divides forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy into anterior/posterior compartments
  • Stabilizes pronation-supination

Functional Anatomy and Movements of the Elbow Joint

The functional anatomy of the elbow is unique secondary to the orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment and multiple articulations. The main function of the elbow is to link the shoulder and the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy and position and stabilize the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy during activities.

Elbow movement and normal range of motion

Range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs and movements of the elbow joint

Image by Lecturio.

Carrying angle:

  • Normal valgus carrying angle: 515 degrees
  • Prevents arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy from contacting hips
  • Women > men, greater in dominant limb (both sexes)
Carrying angle

Carrying angle

Image by BioDigital, edited by Lecturio

Muscles of the Elbow Joint

The muscles of the elbow originate in the upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy and insert into the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, producing flexion-extension of the elbow as well as supination-pronation of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy. The muscles also provide dynamic stabilization to the elbow joint.

Muscle Origin Insertion Nerve supply Function
Brachialis Brachialis Arm: Anatomy muscle Anterior aspect of the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy lateral to the deltoid tuberosity Deltoid tuberosity Arm: Anatomy Ulnar tuberosity Musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy (C5–C7) Flexes the elbow and assists with supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs
Brachioradialis Brachioradialis Forearm: Anatomy muscle Proximal 2 thirds of lateral supracondylar ridge Lateral surface of distal radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy and pre-styloid process Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy (C6) Weak flexor of the elbow, strong flexor when forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy mid-pronated
Biceps Biceps Arm: Anatomy brachii muscle Short head: coracoid process; long head: supraglenoid tubercle Tuberosity of the radius Radius The outer shorter of the two bones of the forearm, lying parallel to the ulna and partially revolving around it. Forearm: Anatomy Musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy (C5–C6) Supinates the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy and assists with elbow flexion Flexion Examination of the Upper Limbs
Triceps brachii Long head: infraglenoid tubercle; lateral and medial heads: posterior humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy Olecranon Olecranon A prominent projection of the ulna that articulates with the humerus and forms the outer protuberance of the elbow joint. Arm: Anatomy Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy (C6–C8) Extends the elbow
Anconeus Inserts on the posterior aspect of lateral epicondyle Lateral epicondyle Arm: Anatomy Lateral surface of the olecranon Olecranon A prominent projection of the ulna that articulates with the humerus and forms the outer protuberance of the elbow joint. Arm: Anatomy Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy (C7, C8) Assists in extension Extension Examination of the Upper Limbs of the elbow and stabilizes the joint

Neurovascular and Lymphatic Supply of the Elbow

Innervation

  • Anteriorly: The musculocutaneous, median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion, and radial nerves pass anterior to the elbow and innervate the anterior capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides.
  • Posteriorly: The ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy passes posteriorly and medially at the elbow and innervates the posterior capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides.
Nerves of the elbow

Nerves of the elbow

Image by BioDigital, edited by Lecturio

Arterial supply

  • Brachial artery Brachial Artery The continuation of the axillary artery; it branches into the radial and ulnar arteries. Cubital Fossa: Anatomy
    • Courses down the anterior surface of the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy into the cubital fossa Cubital Fossa The cubital fossa is the region anterior to the elbow joint. The cubital fossa is seen as the triangular depression between the brachioradialis and pronator teres muscles. The 4 important structures of the cubital fossa (from lateral to medial) are the radial nerve, tendon of the biceps brachii muscle, brachial artery, and median nerve. Cubital Fossa: Anatomy
    • Bifurcates into the radial and ulnar artery Ulnar Artery The larger of the two terminal branches of the brachial artery, beginning about one centimeter distal to the bend of the elbow. Like the radial artery, its branches may be divided into three groups corresponding to their locations in the forearm, wrist, and hand. Forearm: Anatomy in the proximal forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
  • The cubital anastomosis is an extensive circulatory system surrounding the elbow, formed from branches of the brachial, radial, and ulnar arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology.
Arteries of the elbow

Arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology of the elbow

Image by BioDigital, edited by Lecturio

Venous drainage

  • Basilic and cephalic vein: the primary superficial veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology of the upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy
  • Connected at the elbow anteriorly by the median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion cubital vein

Lymphatic drainage

Epitrochlear or cubital lymph nodes Cubital lymph nodes Cubital Fossa: Anatomy are found at the elbow and drain proximally to the axillary lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy.

Clinical Relevance

The following are common conditions related to the elbow:

  • Humerus fracture: A distal humerus fracture primarily occurs from falling on the outstretched arm. Humerus fractures are classified into supra-, trans-, or intercondylar fractures. Depending on the location and the extent of the fractures, these injuries may need to be reduced and addressed surgically. 
  • Supracondylar fracture: a common traumatic fracture in children that occurs from a fall on an outstretched arm or hand. Treatment often includes closed reduction and percutaneous pinning, which may be urgent if the neurovascular system is compromised.
  • Olecranon fracture: occurs secondary to falling on the flexed arm. Depending on the complexity of the fracture, the fracture may be treated surgically with a tension band osteosynthesis.
  • Radial head fracture: One of the most common fractures in adults; occurs secondary to falling on the extended arm. Can occur with or without dislocation and may include multiple fragments. May require surgical management.
  • Elbow dislocation: 2nd-most common joint dislocation after the shoulder. A fall on an outstretched hand is the usual mode of injury. Complex elbow dislocations have an associated fracture or neurovascular injury.
  • Nursemaid’s elbow (radial head subluxation): also called “babysitter’s elbow.” Common injury of young children that occurs secondary to longitudinal traction on the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy and forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy. Causes a subluxation Subluxation Radial Head Subluxation (Nursemaid’s Elbow) of the annular Annular Dermatologic Examination ligament from the normal location surrounding the radial head. Treatment is usually closed reduction Closed Reduction Radial Head Subluxation (Nursemaid’s Elbow) using a supination technique Supination Technique Radial Head Subluxation (Nursemaid’s Elbow).
  • Medial/lateral epicondylitis or flexor/extensor tendinosis: a common problem of the elbow, with localized pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways at either the lateral (extensor) or medial (flexor) epicondyle. Associated with inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation or degeneration of the tendons of the area due to repetitive microtrauma Microtrauma Small injuries caused by external force applied to the body including bones, muscles, nerves and tendons. Osgood-Schlatter Disease/overuse. Medial epicondylitis or flexor tendinosis is also known as “golfer’s elbow,” while lateral epicondylitis or extensor tendinosis is known as “ tennis elbow Tennis elbow A condition characterized by pain in or near the lateral humeral epicondyle or in the forearm extensor muscle mass as a result of unusual strain. It occurs due repetitive stresses on the elbow from activities such as tennis playing. Examination of the Upper Limbs.”
  • Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy compression Compression Blunt Chest Trauma syndrome: also called cubital tunnel syndrome. Usually due to a direct trauma Direct Trauma Toddler’s Fractures of the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy or repetitive/prolonged elbow flexion Flexion Examination of the Upper Limbs. Less commonly secondary to hypermobility of the ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy or osteophytes in the cubital tunnel.

References

  1. Drake, R.L., Vogl, A.W., & Mitchell, A.W.M. (2014). Gray’s Anatomy for Students (3rd ed.). Philadelphia, PA:  Churchill Livingstone.

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