Navigate Up
Sign In

Posterior Antebrachial Cutaneous (PABC)

Key Points:
• Examination of this nerve includes testing the skin in the posterior aspect of the forearm.
Sensory Innervation:
• Provides sensation to the posterior cutaneous aspect of the forearm.
• Originates from roots C5, C6, C7, C8 and branches from the radial nerve.
Sensory examination includes testing the posterior aspect of the forearm innervated by the posterior antebrachial cutaneous nerve.
Sensory Examination:
• Ask patients to draw area of diminished sensation/numbness on a body diagram.
• Test the skin along the posterior aspect of the forearm for reduced/absent sensation by use of light touch or other sensory examination modalities.
Clinical Relevance:
• Provides sensation to the posterior aspect of the forearm. 
Adjacent Sensory Distribution:
PROXIMAL – Posterior brachial cutaneous nerve.
MEDIAL – Medial antebrachial cutaneous nerve.
LATERAL – Lateral antebrachial cutaneous nerve.
DISTAL/MEDIAL – Dorsal cutaneous branch of the ulnar nerve.
DISTAL/LATERAL – Superficial radial nerve.
Relevant Anatomy:
• Roots: C5, C6, C7, C8.
• Nerve: Radial nerve.
• Sensory Territory: Posterior aspect of the forearm.
• Innervation Route: C5, C6, C7, C8 → radial nerve → posterior antebrachial cutaneous.
Course: The posterior antebrachial cutaneous nerve branches from the radial nerve just distal to the posterior brachial cutaneous nerve (PBC) in the axilla and they course through the arm in close proximity to each other. In the proximal forearm, the posterior antebrachial cutaneous nerve is found exactly on the lateral border of the brachioradialis muscle.  As it continues distally, the terminal branches innervate the posterior aspect of the forearm.