Human Anatomy Vol 1

INTRODUCIION

This chapter deals mainly
connect the upper limb with

with structures which

the back of the trunk.

The scapula (shoulder blade) is placed on the

posterolateral aspect of the upper part of the thorax.

It extends from the second to the seventh ribs.

Although it is thickly covered by muscles, most of its

outline can be felt in the living subject. Tlne acromion

lies at the top of the shoulder. The crest of the spine of

the scapula runs from the acromion medially and

slightly downwards to the medial border of the

scapula. The medial border and the inferior angle of the

scapula can also be palpated (Fig. 5.1).

The eighth rib is jrtst below the inferior angle of the

scapula. The lower ribs can be identified on the back

by counting down from the eighth rib.

The iliac crest is a curved bony ridge lying below the

waist. The anterior end of the crest is the anterior

superior iliac spine.The posterior superior iliac spine is

felt in a shallow dimple above the buttock, about

5 cm from the median plane.

The sacrum lies between the right and left dimples

mentioned above. Usually three sa*al spines are

palpable in the median plane.

The coccyx lies between the two buttocks in the

median plane.

The spine of the seventh cervical vertebra or oertebra

prominens is readily felt at the root of the neck. Higher

up on the back of the neck, the second ceraical spine

can be felt about 5 cm below the external occipital

protuberance. Other spines that can be recognised are

T3 at the level of root of the spine of the scapula, L4

at the level of the highest point of the iliac crest, and

52 at the level of the posterior superior iliac spine.

-Alexonder Pope

7 The junction of the back of the head with that of the

neck is indicated by the external occipital

protuberance and the superior nuchal lines. The

external occipital protuberance is a bony projection felt

in the median plane on the back of the head at the

upper end of the nuchal furrow (running vertically

on the back of the neck). T}":re superior nuchal lines are

indistinct curved ridges which extend on either side

from the protuberance to the mastoid process. The

nuchal furrow extends to the external occipital

protuberance, above, and to the spine of C7 below.

D]SSECTION

ldentify the external occipital protuberance (i) of the

skull. Draw a line in the midline from the protuberance

to the spine of the last thoracic (T12) vertebra (ii) Make

incision along this line (Fig.5.1). Extend the incision

from its lower end to the deltoid tuberosity (iii) on the

humerus which is present on lateral surface about the

middle of the arm. Note that the arm is placed by the

side of the trunk.

Make another incision along a horizontal line from

seventh cervical spine (iv) to the acromion process of

scapula (v). Reflect the skin flap laterally.

Posilion

Man mostly lies on his back. Therefore, the skin and

fasciae of the back are adapted to sustain pressure of

the body weight. Accordingl/, the skin is thick and

fixed to the underlying fasciae; the superficial fascia

containing variable amount of fat, is thick and strong

and is connected to overlying skinby connective tissue;

and the deep fascia is dense in texture.