Axillary Nerve
Description
Alternative Names
- Circumflex nerve
- Circumflex humeral nerve
- Posterior circumflex nerve
- Nervus axillaris
- Deltoid nerve (historical/rare)
Overview
- Nerve roots: C5, C6.
- Sensory functions: innervates the skin over the lower deltoid (‘regimental badge area’)
- Motor functions
Anatomic Course
- Formed within the axilla of the upper limb
- Direct continuation of the posterior cord of the brachial plexus
- Contains nerve roots fro C5, C6
- In the axilla, located posterior to axillary artery, anterior to subscapularis
- Exits axilla at the inferior border of subscapularis via quadrangular space
- Often accompanied by circumflex humeral artery and vein
- Then passes medially to the surgical neck of the humerus
- Here, it divides into 3 terminal branches
Posterior Terminal Branch
- Motor innervation to posterior aspect of deltoid muscle and teres minor
- Sensory innervation of skin over inferior deltoid (via upper lateral cutaneous nerve of the arm)
Anterior Terminal Branch
- Wraps around the surgical neck of the humerus
- Provides motor innervation to anterior aspect of deltoid
- Cutaneous branches of the anterior, anterolateral should
Articular Branch
- Supplies the glenohumeral joint
- Anatomic gap in which the axillary nerve is transmitted from the anterior axilla to the poster shoulder and arm
- Superior: inferior aspect of teres minor
- Inferior: superior aspect of teres major
- Lateral: surgical neck of humerus
- Medial: long head of triceps brachii
- Anterior: subscapularis
Motor Functions
Sensory: Superior Lateral Cutaneous Nerve of the Arm
- Delivered via its posterior terminal branch
- Continues as upper lateral cutaneous nerve of the arm (after terminal branch to teres minor)
- Often called the regimental badge area (skin over the inferior portion of the deltoid)
Clinical Significance
See Also
References
- ↑ Image courtesy of https://step1.medbullets.com/
- ↑ Orellana-Donoso, Mathias, et al. "Neural entrapments associated with musculoskeletal anatomical variations of the upper limb: Literature review." Translational Research in Anatomy 22 (2021): 100094.
- ↑ Thimjon, Connor, et al. "C6 and not C5 nerve fibers more commonly contribute most to deltoid muscle innervation: anatomical study with application to better diagnosing cervical nerve injuries." Neurosurgical Review 45.3 (2022): 2401-2406.