Fill in the information for the items marked with a * Chapter 13 continued Fill in the information for the items marked with a * © 2013 Pearson Education, Inc.

C. Spinal Nerves 1. General Information *Number: all mixed nerves b) Naming: Most exit inferior to vertebra Cervical: #1-8 C1 exits superior to vertebra #1 *Thoracic: *Lumbar: *Sacral: Coccygeal: 1= C0 c) *Exit Spinal Column via: © 2013 Pearson Education, Inc.

Spinal Nerves Cervical plexus Cervical nerves C1 – C8 Brachial plexus enlargement Thoracic nerves T1 – T12 Intercostal nerves Lumbar enlargement Lumbar nerves L1 – L5 Lumbar plexus Sacral plexus Sacral nerves S1 – S5 Cauda equina Coccygeal nerve Co1

Spinal Nerves … d) Spinal Nerves Roots *Formation of Spinal Nerves by fusion of: *Length of Spinal Nerves: Ventral root Dorsal root Dorsal and ventral rootlets of spinal nerve Dorsal root ganglion Ventral ramus of spinal nerve Spinal nerve Rami communicantes

2. Branches of Spinal Nerves: Rami *Dorsal ramus: *Ventral ramus: form plexuses in all but T2-T12 Rami Communicates Dorsal ramus Ventral ramus Spinal nerve Rami communicantes

Branches of intercostal nerve Dorsal ramus Ventral ramus Spinal nerve Rami communicantes Intercostal nerve Sympathetic trunk ganglion Dorsal root ganglion Dorsal root Ventral root Branches of intercostal nerve • Lateral cutaneous • Anterior cutaneous Sternum (b) Cross section of thorax showing the main roots and branches of a spinal nerve. Figure 13.7 (b)

3. *Plexuses = *Formed from: b) Not all Ventral Rami do this: T2-T11 c) Number of Plexuses: d) Final Product = Mixed Systemic Nerves: Function: *most carry somatic sensory and autonomic to and from skin Brachial Plexus © 2013 Pearson Education, Inc.

4) Cervical Plexus a) *Ventral rami of: b) *Body Location: c) Sytemic Nerves Phrenic nerve Serves:) Phrenic © 2013 Pearson Education, Inc.

5) Brachial Plexus and Upper Limb a) *Ventral Rami: b) *Body Locations: c) Major branches of this plexus: Roots—five ventral rami (C5– T1), which form Trunks—upper, middle, and lower, which form Divisions—2 anterior & 3 posterior, which form Cords—lateral, medial, and posterior Trunks C4 Posterior* Divisions Cords Posterior Lateral T1 Anterior Divisions * Medial M shape © 2013 Pearson Education, Inc.

Roots (rami C5–T1), trunks, divisions, and cords Figure 13.10a The brachial plexus. Anterior divisions Posterior divisions Trunks Roots Roots (ventral rami): C4 Dorsal scapular C5 Nerve to subclavius C6 Suprascapular Upper Posterior divisions C7 Middle Trunks C8 Lateral Lower Cords T1 Posterior Long thoracic Medial Medial pectoral Lateral pectoral Axillary Upper subscapular Musculo- cutaneous Lower subscapular Thoracodorsal Radial Medial cutaneous nerves of the arm and forearm Median Ulnar Roots (rami C5–T1), trunks, divisions, and cords © 2013 Pearson Education, Inc.

5) Brachial Plexus … d) Systemic Nerves of Brachial Plexus i) 3 Nerves form a “M” shape: They are more anterior and superficial and come off the Lateral and Medial cords. *Musculocutaneous: Muscels innervated = Median: to lateral forearm to innervate hand flexors Ulnar: to medial forearm to innervate medial hand flexors Musculocutaneous nerve Lateral cord Posterior cord Axillary nerve Medial cord Radial nerve Median nerve Ulnar nerve © 2013 Pearson Education, Inc. Cadaver photo

Musculocutaneous nerve Axillary nerve Humerus Radial nerve Musculocutaneous nerve Ulna Radius Ulnar nerve Median nerve Radial nerve (superficial branch) Dorsal branch of ulnar nerve Superficial branch of ulnar nerve Digital branch of ulnar nerve Muscular branch Median nerve Digital branch © 2013 Pearson Education, Inc.

© 2013 Pearson Education, Inc.

*Radial: Muscles innervated = wrist drop ii) Nerves branch off Posterior Cord and move posteriorly and deep just below head of humerus *Radial: Muscles innervated = wrist drop Axillary—to armpit: Serves: deltoid, teres minor muscles Musculocutaneous nerve Lateral cord Posterior cord Axillary nerve Medial cord Radial nerve Median nerve Ulnar nerve Cadaver photo © 2013 Pearson Education, Inc.

© 2013 Pearson Education, Inc.

Musculocutaneous nerve Axillary nerve Humerus Radial nerve Musculocutaneous nerve Ulna Radius Ulnar nerve Median nerve Radial nerve (superficial branch) Dorsal branch of ulnar nerve Superficial branch of ulnar nerve Digital branch of ulnar nerve Muscular branch Median nerve Digital branch © 2013 Pearson Education, Inc.

Long Thoracic– is long, innervates Serratus Anterior iii) Nerves that can be seen at muscles they innervate (or as they go there) Long Thoracic– is long, innervates Serratus Anterior *Pectoral Nerves (medial and lateral): Suprascapular: travels at top of shoulder to supraspinatus. Also infraspinatus. Comes off before Trunks superiorly, right before lateral cord *Subscapular (Upper and Lower): Comes off Posterior Cord above where radial nerve begins Thoracodorsal– to Latissamus Dorsi Suprascapular Long thoracic pectoral subscapular Thoracodorsal © 2013 Pearson Education, Inc.

6) Lumbosacral Plexus: a) Lumbar Plexus = lumbar and sacral plexuses overlap, so often combined. Serves mainly lower limb a) Lumbar Plexus Arises from L1–L4 (L5) *Femoral nerve—Comes through Groin area with veins/arteries; Muscles = Saphenous nerve– *hip and knee joints, skin Branch of Femoral nerve *Obturator nerve— travels to medial thigh to innervate = Femoral Obturator Saphenous © 2013 Pearson Education, Inc.

Figure 13.11 The lumbar plexus. Ventral rami Ventral rami: L1 Iliohypogastric Ilioinguinal L2 Iliohypogastric Femoral Lateral femoral cutaneous Ilioinguinal L3 Genitofemoral Obturator Lateral femoral cutaneous Anterior femoral cutaneous L4 Saphenous Obturator L5 Femoral Lumbosacral trunk Ventral rami and major branches of the lumbar plexus Distribution of the major nerves from the lumbar plexus to the lower limb © 2013 Pearson Education, Inc.

Table 13.5 Branches of the Lumbar Plexus © 2013 Pearson Education, Inc.

b) Sacral Plexus i) Arises from L4–S4 ii) Serves: mainly posterior thigh & leg, but also buttock, pelvic structures, and perineum iii) Sciatic nerve L4 – S3 Longest and thickest nerve of body *Serves: prior to branching, serves muscles = -- *Proximal to Knee, Sciatic branches into what two nerves? Sciatica: Sciatic Nerve Common fibular Tibial © 2013 Pearson Education, Inc.

Ventral rami and major branches of the sacral plexus Figure 13.12a The sacral plexus. Ventral rami Ventral rami: L4 Superior gluteal L5 Lumbosacral trunk S1 Inferior gluteal S2 Common fibular Tibial S3 Posterior femoral cutaneous S4 Pudendal S5 Sciatic Co1 Ventral rami and major branches of the sacral plexus © 2013 Pearson Education, Inc.

Gluteus maximus Piriformis Inferior gluteal nerve Common fibular nerve Figure 13.12c The sacral plexus. Gluteus maximus Piriformis Inferior gluteal nerve Common fibular nerve Tibial nerve Pudendal nerve Posterior femoral cutaneous nerve Sciatic nerve Cadaver photo © 2013 Pearson Education, Inc.

iv) Tibial Nerve: on Tibia side (medial) *Serves: posterior thigh and leg muscles = It eventually branches into the plantar nerves, medial and lateral Sciatic Posterior femoral cutaneous Common fibular Tibial Deep fibular Superficial fibular Plantar branches © 2013 Pearson Education, Inc.

Before Branch it Serves: biceps femoris Common Fibular Nerve : on fibula side Before Branch it Serves: biceps femoris *Branches into what two nerves: Branches Serve: Externsor Digitorum Longus and Tibialis anterior Sciatic Common fibular Tibial Deep fibular Superficial fibular Plantar branches © 2013 Pearson Education, Inc.

END PPT © 2013 Pearson Education, Inc.