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Upper arm and elbow

Last updated: November 27, 2020

Summarytoggle arrow icon

The upper arm, or brachium, extends between the shoulder joint and elbow. The shoulder joint connects the upper arm to the torso and the shoulder girdle, while the elbow joint connects it to the forearm. The muscles of the upper arm move the elbow joint (flexion and extension) and the forearm (pronation and supination), as well as stabilize and move the shoulder joint (internal rotation and flexion). This article covers the bones, muscles, vasculature, lymphatics, and innervation of the upper arm and elbow.

See “Forearm, wrist, and hand” and “Shoulder, axilla, and brachial plexus.”

Definition

The humerus is a bone of the arm that articulates proximally with the scapula to form the shoulder joint and distally with the radius and ulna to form the elbow joint.

Head of the humerus

Neck of the humerus

Shaft of the humerus

“Broken ARM:” the Axillary, Radial, and Median nerves can be injured as a result of a humerus fracture.

Tendinosis at the medial epicondyle (medial epicondylitis) is called golfer's elbow. Tendinosis at the lateral epicondyle (lateral epicondylitis) is called tennis elbow.References:[1]

The muscles of the arm can be categorized into two groups: flexors and extensors. They lie deep to the brachial fascia and are divided into anterior (flexor) and posterior (extensor) compartments by the medial intermuscular septum and the lateral intermuscular septum.

For specific tests to assess the function of these muscles, see “Motor function” in “Neurological examination.”

Anterior compartment of the arm (flexors)

The anterior compartment contains three muscles that are elbow flexors, all of which are innervated by the musculocutaneous nerve.

Overview of the muscles of the anterior compartment of the arm
Muscle Biceps brachii

Brachialis

Coracobrachialis

Origin
Insertion
  • Ulnar tuberosity
Innervation
Function

The elbow flexors are innervated by the musculocutaneous nerve.

Posterior compartment of the arm (extensors)

The posterior compartment contains two muscles that are elbow extensors, both of which are innervated by the radial nerve.

Overview of the muscles of the posterior compartment of the arm
Muscle Triceps brachii Anconeus muscle
Origin
Insertion
Innervation
Function

The elbow extensors are innervated by the radial nerve.

Muscle grooves of the arm

There are two bicipital grooves between the muscle groups of the arm that serve as channels for important neurovascular pathways. They are different from the bicipital groove that lies between the tubercles of the humerus.

Medial bicipital groove Lateral bicipital groove
Location
Arteries

Veins

Nerves

Arterial supply

The brachial artery is the main artery of the arm, forearm, and hand.

The brachial artery can be compressed proximally against the medial humerus to stop bleeding in the distal arm.

Venous drainage

Lymphatic drainage

Motor and sensory innervation of the arm and elbow

Overview of the innervation of the arm and elbow
Function Nerve Innervated structures

Motor

Sensory

  • Inferomedial aspect of the arm
  • Superior lateral brachial cutaneous nerve (branch of the axillary nerve)
  • Inferior aspect of the deltoid
  • Inferior lateral brachial cutaneous nerve (branch of the radial nerve)
  • Inferolateral aspect of the arm
  • Posterior brachial cutaneous nerve (branch of the radial nerve)

See “Nerve injuries in the upper body” in “Peripheral nerve injuries” and “Motor function” and “Sensation” in “Neurological examination.”

Dermatomal distribution of the arm

Radial head subluxation (nursemaid elbow), partial subluxation of the radial head at the radiohumeral joint, is caused by excessive axial traction. It is the most common elbow injury in children < 5 years of age.

References:[2]

The median cubital vein of the antecubital fossa is one of the most common sites for peripheral venipuncture and intravenous access.

The epitrochlear lymph nodes are classically enlarged in syphilis and/or sarcoidosis.

Really Need Beer To Be At My Nicest:” the contents of the cubital fossa are (from lateral to medial) Radial Nerve, Biceps Tendon, Brachial Artery, and Median Nerve.References:[4]

  1. Frontera WR, Silver JK, Rizzo TD. Essentials of Physical Medicine and Rehabilitation E-Book. Elsevier Health Sciences ; 2014
  2. Catalano O, Nunziata A, Saturnino PP, Siani A. Epitrochlear lymph nodes: Anatomy, clinical aspects, and sonography features. Pictorial essay. J Ultrasound. 2010; 13 (4): p.168-74. doi: 10.1016/j.jus.2010.10.010 . | Open in Read by QxMD
  3. Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier Health Sciences ; 2016
  4. Dhillon MS, Gopinathan NR, Kumar V. Misconceptions about the three point bony relationship of the elbow. Indian J Orthop. 2014; 48 (5): p.453-7. doi: 10.4103/0019-5413.139835 . | Open in Read by QxMD