Brachial and Lumbar Plexus Evaluation

Brachial Plexus

• Axillary n.: responsible for abduction of the deltoids and sensation in the skin over the deltoid muscle
• Intercostal brachial n.: provides sensory innervation to the axilla and ribs near the axilla
• Medial brachial cutaneous n.: supplies sensory innervation to the skin of the medial upper arm
• Medial antebrachial cutaneous n.: supplies sensory innervation to the skin of the medial lower arm
• Radial n.: responsible for motor function of extensors of the fingers, wrist, and elbow, and for sensory innervation of the skin of the anatomical snuff box (posterior skin between the thumb and index finger)
• Musculocutaneous n.: responsible for flexion at the elbow (biceps) and supplies sensory innervation to the skin of the lateral forearm
• Median n.: responsible for motor function of wrist flexors and supplies sensory innervation to the skin of the thenar eminence
• Ulnar n.: responsible for motor function of abducting and adducting fingers, and supplies sensory innervation to the skin at the base of the little finger, skin of the little finger, and a portion of the ring finger

Lumbar and Sacral Plexus

• Lateral femoral cutaneous n.: supplies sensory innervation to the lateral upper thigh
• Femoral n.: supplies sensory innervation to the remainder of the skin of the anterior upper thigh to the knee, and is responsible for motor function of knee extensors, quads, sartorius, and other muscles
• Saphenous n.: supplies sensory innervation from the medial aspect of the lower leg, knee to the medial malleolus
• Obturator n.: supplies sensory innervation to some sources say a medial patch of skin at the knee, and part of the knee joint, and is responsible for motor function of adductors of the leg
• Sciatic n.: has a Common Peroneal n. branch that supplies sensory innervation to the skin of the lower lateral leg and enables dorsiflexion of the foot
• Superficial branch of the peroneal n.: supplies sensory innervation to the skin over the top of the foot
• Deep branch of the peroneal n.: supplies sensory innervation to the skin between the first and second toes, and bones of the upper foot
• Posterior tibial n.: has a sensory branch that supplies sensory innervation to the skin on the plantar surface of the foot, and is responsible for motor function of extensors of the foot and plantar flexion of the foot
• Sural n.: supplies sensory innervation to the skin over the heel

Brachial Plexus

• Axillary n.: responsible for abduction of the deltoids and sensation in the skin over the deltoid muscle
• Intercostal brachial n.: provides sensory innervation to the axilla and ribs near the axilla
• Medial brachial cutaneous n.: supplies sensory innervation to the skin of the medial upper arm
• Medial antebrachial cutaneous n.: supplies sensory innervation to the skin of the medial lower arm
• Radial n.: responsible for motor function of extensors of the fingers, wrist, and elbow, and for sensory innervation of the skin of the anatomical snuff box (posterior skin between the thumb and index finger)
• Musculocutaneous n.: responsible for flexion at the elbow (biceps) and supplies sensory innervation to the skin of the lateral forearm
• Median n.: responsible for motor function of wrist flexors and supplies sensory innervation to the skin of the thenar eminence
• Ulnar n.: responsible for motor function of abducting and adducting fingers, and supplies sensory innervation to the skin at the base of the little finger, skin of the little finger, and a portion of the ring finger

Lumbar and Sacral Plexus

• Lateral femoral cutaneous n.: supplies sensory innervation to the lateral upper thigh
• Femoral n.: supplies sensory innervation to the remainder of the skin of the anterior upper thigh to the knee, and is responsible for motor function of knee extensors, quads, sartorius, and other muscles
• Saphenous n.: supplies sensory innervation from the medial aspect of the lower leg, knee to the medial malleolus
• Obturator n.: supplies sensory innervation to some sources say a medial patch of skin at the knee, and part of the knee joint, and is responsible for motor function of adductors of the leg
• Sciatic n.: has a Common Peroneal n. branch that supplies sensory innervation to the skin of the lower lateral leg and enables dorsiflexion of the foot
• Superficial branch of the peroneal n.: supplies sensory innervation to the skin over the top of the foot
• Deep branch of the peroneal n.: supplies sensory innervation to the skin between the first and second toes, and bones of the upper foot
• Posterior tibial n.: has a sensory branch that supplies sensory innervation to the skin on the plantar surface of the foot, and is responsible for motor function of extensors of the foot and plantar flexion of the foot
• Sural n.: supplies sensory innervation to the skin over the heel

Upper Extremity Nerves

• Axillary nerve: responsible for sensory and motor functions in the upper extremity
• Radial nerve: performs sensory and motor functions in the upper extremity
• Musculocutaneous nerve: has sensory and motor functions in the upper extremity
• Median nerve: involved in sensory and motor functions in the upper extremity
• Ulnar nerve: responsible for sensory and motor functions in the upper extremity
• Intercostal brachial nerve: has sensory and motor functions in the upper extremity
• Medial brachial cutaneous nerve: performs sensory functions in the upper extremity
• Medial antebrachial cutaneous nerve: responsible for sensory functions in the upper extremity

Lower Extremity Nerves

• Lateral femoral cutaneous nerve: involved in sensory functions in the lower extremity
• Femoral and Saphenous nerve: performs sensory and motor functions in the lower extremity
• Obturator nerve: responsible for sensory and motor functions in the lower extremity
• Sciatic nerve: involved in sensory and motor functions in the lower extremity
• Tibial nerve: performs sensory and motor functions in the lower extremity
• Peroneal nerve: responsible for sensory and motor functions in the lower extremity

Upper Extremity Nerves

• Axillary nerve: responsible for sensory and motor functions in the upper extremity
• Radial nerve: performs sensory and motor functions in the upper extremity
• Musculocutaneous nerve: has sensory and motor functions in the upper extremity
• Median nerve: involved in sensory and motor functions in the upper extremity
• Ulnar nerve: responsible for sensory and motor functions in the upper extremity
• Intercostal brachial nerve: has sensory and motor functions in the upper extremity
• Medial brachial cutaneous nerve: performs sensory functions in the upper extremity
• Medial antebrachial cutaneous nerve: responsible for sensory functions in the upper extremity

Lower Extremity Nerves

• Lateral femoral cutaneous nerve: involved in sensory functions in the lower extremity
• Femoral and Saphenous nerve: performs sensory and motor functions in the lower extremity
• Obturator nerve: responsible for sensory and motor functions in the lower extremity
• Sciatic nerve: involved in sensory and motor functions in the lower extremity
• Tibial nerve: performs sensory and motor functions in the lower extremity
• Peroneal nerve: responsible for sensory and motor functions in the lower extremity

Brachial Plexus

Definition and Function

• A complex network of nerves that originates in the neck and shoulder region, controlling muscle movements and sensations in the upper limb
• Responsible for both motor and sensory functions

Anatomy and Structure

• Formed by the ventral rami of C5-T1 spinal nerves
• Composed of five distinct components:
  • Roots: C5-T1 spinal nerves
  • Trunks: 3 main trunks (superior, middle, inferior)
  • Divisions: anterior and posterior divisions of each trunk
  • Cords: 3 cords (lateral, medial, posterior)
  • Branches: final branches that form the peripheral nerves of the upper limb

Motor Functions

• Controls movements of the shoulder, arm, forearm, and hand
• Innervates muscles of the upper limb

Sensory Functions

• Transmits sensory information from the upper limb to the central nervous system

Clinical Relevance and Injuries

• Injuries can result from trauma (e.g., falls, motor vehicle accidents), birth injuries (e.g., dystocia), or tumors/space-occupying lesions
• Symptoms of brachial plexus injuries include:
  • Weakness or paralysis of the upper limb
  • Numbness or paresthesia in the arm or hand
  • Pain or burning sensations in the arm or hand

This quiz covers the sensory and motor evaluation of the brachial and lumbar plexus, including the axillary nerve, intercostal brachial nerve, and radial nerve. It focuses on the motor and sensory functions of each nerve.