The Thoracic wall is covered by:
From superficial to deep,
- Superficial fascia.
- Deep fascia.
Anterior aspect and rear aspect of the skin covering the thoracic wall are thin and thick respectively. Age, gender and race are the factors to depend upon the distribution of hair which is variable.
Cutaneous nerves: The cutaneous innervation on the front of thorax is offered by cutaneous branches of anterior primary rami of thoracic spinal nerves (T2 -T6) in sequence from above downwards by the T2 at the level of 2nd rib to the T6 at the level of xiphoid process. The skin above the level of 2nd rib is provided by the anterior primary ramus of C4 via supraclavicular nerves.
- The anterior rami of C5 T1 innervate the skin of the upper limb.
- The cutaneous innervation on the rear of thorax (on either side of midline for about 5 cm) is supplied by posterior rami of thoracic spinal nerves.
The superficial fascia is more dense on the posterior aspect of the chest to keep up the pressure of the body when being located in the supine position. The superficial fascia on the very front of the chest includes breast (mammary gland), that is rudimentary in males and well- grown in adult females.
The deep fascia is thin and ill defined (with the exception of in pectoral region) to enable free movement of the thoracic wall during breathing.
The thoracic wall is liberally covered by the following extrinsic muscles:
Muscles Of Upper Limb:
- Pectoralis major and pectoralis minor muscles cover the front of thoracic wall.
- Serratus anterior covers the side of thoracic wall.
Muscles Of Abdomen
Rectus abdominis and external oblique covers the lower part of the front of thoracic wall.
Muscles Of Back
- Trapezius and latissimus dorsi.
- Levator scapulae, rhomboideus major and minor.
- Serratus – posterior, superior, and inferior.
- Erector spinae.
The thoracic wall is more or less fully covered by extrinsic muscles with the exception of in the anterior and posterior median lines.
On the back, the thoracic wall is thinly covered by musculature in the region of triangle of auscultation.