CERVICAL PLEXUS REVIEW

Question 1

What are the ROOTS of CERVICAL PLEXUS?

Answer 1

C1-C4 (with contributions from C5)

Question 2

Name 1 of the SUPERFICIAL (SENSORY) BRANCHES and what it INNERVATES? (1 out of 4)

Answer 2

1) LESSER OCCIPITAL NERVE (C2)

- skin of scalp posterior and anterior to ear.

Question 3

Name 1 of the SUPERFICIAL (SENSORY) BRANCHES and what it INNERVATES? (2 out of 4)

Answer 3

2) GREAT AURICULAR NERVE (C2-C3)
-skin anterior, inferior and over ear & over Parotid
glands

Question 4

Name 1 of the SUPERFICIAL (SENSORY) BRANCHES and what it INNERVATES? (3 out of 4)

Answer 4

3) TRANSVERSE CERVICAL NERVE (C2-C3)

- skin over anterior aspect of neck

Question 5

Name 1 of the SUPERFICIAL (SENSORY) BRANCHES and what it INNERVATES? (4 of 4)

Answer 5

4) SUPRACLAVICULAR NERVE (C3-C4)

- skin over superior portion of chest and shoulder

Question 6

Name 1 of the DEEP (MOSTLY MOTOR) BRANCHES and what it INNERVATES? (1 of 4)

Answer 6

1. ANSA CERVICALIS: divides into SUPERIOR &
   INFERIOR ROOTS

SUPERIOR ROOT (C1)
-Infrahyoid & geniohyoid muscles of neck

Question 7

Name 1 of the DEEP (MOSTLY MOTOR) BRANCHES and what it INNERVATES? (2 of 4)

Answer 7

2. INFERIOR ROOT (of ansa cervicalis) (C2-C3)

- Infrahyoid muscles of neck

Question 8

Name 1 of the DEEP (MOSTLY MOTOR) BRANCHES and what it INNERVATES? (3 of 4)

Answer 8

3. PHRENIC NERVE (C3-C5)

- Diaphragm

Question 9

Name 1 of the DEEP (MOSTLY MOTOR) BRANCHES and what it INNERVATES? (4 of 4)

Answer 9

4. SEGMENTAL BRANCHES (C1-C5)
   -prevertebral (deep) muscles of neck, levator
   scapulae, middle scalenes

Question 10

What are the ROOTS of LUMBAR PLEXUS?

Answer 10

Ventral Rami L1-L4 + a branch of the SUBCOSTAL NERVE (T12)

Question 11

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (1 of 7)

Answer 11

1) ILIOHYPOGASTRIC NERVE (L1)
INNERVATION: muscles of ANTEROLATERAL
ABDOMINAL WALL; skin of INF. ABDOMEN &
BUTTOCK

DESCRIPTION: emerges from superolateral border
Psoas major, crosses obliquely in front Quadratus
lumborum to Iliac crest.
-then perforates posterior Transversus abdominis and
divides b/w that muscle and Obliquus internus
abdominis into LATERAL and ANT. CUTANEOUS
BRANCH

Question 12

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (2 of 7)

Answer 12

2) ILIOINGUINAL NERVE (L1)
INNERVATION: Muscles of anterolateral
ABDOMINAL WALL, SKIN of sup. & med. aspects of
THIGH, ROOT of PENIS & SCROTUM (male) & LABIA
MAJORA & MONS PUBIS (female).

DESCRIPTION: Emerges from LAT. border of Psoas
major, just inferior to iliohypogastric, passing
obliquely across Quadratus Lumborum and Iliacus,
perforates Transversus abdominis, near anterior iliac
crest, and communicates with Iliohypogastric N. b/w
Transverus & Obliquus internus.
-Nerve then pierces Ob. internus distributing filaments
to it, accompanying Spermatic cord thru
subcutaneous Inguinal ring, is distributed to skin of
Upper & Medial thigh to skin over Root of Penis and
upper part of Scrotum or skin covering Mons Pubis
and Labia (female)

Question 13

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (3 of 7)

Answer 13

3) GENITOFEMORAL NERVE (L1/L2)
INNERVATION: CREMASTER MUSCLE; skin over middle
anterior surface of thigh, scrotum(m), labia majora(f)

DESCRIPTION: passes obliquely thru Psoas major,
emerging from its medial border close to vert. column
b/w L3/4
-it descends on surface of Psoas maj. under cover of
peritoneum and divides into EXTERNAL SPERMATIC
and LUMBOINGUINAL NERVES
-occasionally these 2 nerves emerge separately thru
the substance of the psoas

Question 14

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (4 of 7)

Answer 14

4) LATERAL FEMORAL CUTANEOUS NERVE (L2/L3)
INNERVATION: skin over lateral, anterior & posterior
aspects of the thigh.

DESCRIPTION: arises from DORSAL DIVISIONS of the
2nd and 3rd LUMBAR NERVES
-emerges from LATERAL border of Psoas maj. and
crosses iliacus obliquely, t/w ASIS. Then passes
under INGUINAL LIGAMENT and over SARTORIUS
into thigh, where it divides into 2 branches:
ANTERIOR and POSTERIOR.

Question 15

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (5 of 7)

Answer 15

5) FEMORAL NERVE (L2-L4)
INNERVATION: largest nerve arising from LP
-distributed to FLEXOR MUSCLES of HIP &
EXTENSOR MUSCLES of KNEE, skin over ant. and
med. aspect of thigh and medial side of leg and foot.

DESCRIPTION: arises from DORSAL DIVISION of
2nd, 3rd and 4th LUMBAR NERVES
- descends through fibres of Psoas maj, emerging from
muscle at lower lateral border; passes down b/w it
and Iliacus, behind iliac fascia; runs beneath
INGUINAL LIGAMENT, into THIGH and splits into an
ANT. and POST. DIVISION
-under inguinal lig. its separated from femoral artery by
a portion of Psoas major

Question 16

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (6 of 7)

Answer 16

6) OBTURATOR NERVE (L2-L4)
INNERVATION: motor-ADDUCTOR MUSCLES of hip joint.
sensory-skin over MED. ASPECT of THIGH
specific muscles(3 Ducks Pecking Grass Outside)
ADDUCTOR LONGUS, BREVIS, MAGNUS (ant. head),
PECTINEUS (+ femoral), GRACILIS, OBTURATOR EXT.

DESCRIPTION: arises from VENTRAL DIVISIONS 2nd, 3rd and 4th LUMBAR NERVES.
-3rd branch is largest, 2nd very small.
-descends thru Psoas major, emerges at medial border
near PELVIS, passes behind COMMON ILIAC
VESSELS and on lateral side of HYPOGASTRIC
VESSELS and UTERER, which separate it from ureter,
run along lateral wall of lesser pelvis, above and in
front of OBTURATOR VESSELS to superior part of
OBTURATOR FORAMEN.
-Here it enters THIGH and divides into ANTERIOR and
POSTERIOR BRANCH which are separated at first by
some of the fibres of OBTURATOR EXTERNUS, and
lower down by ADDUCTOR BREVIS

Question 17

Name 1 of the DIRECT BRANCHES of LUMBAR PLEXUS and what does it innervate? (7 of 7)

Answer 17

7) occasionally the ACCESSORY OBTURATOR NERVE

(L3/4)