[0] Basis 2016-1017 - 2nd Lecture.pdf

Basis of Human Anatomy Dr Hossam Yahia 2nd Lecture Fascia In Latin words, fascia means “band” ‫ﻓﻲ اﻟﻠﻐﺔ اﻟﻌﺮﺑﻴﺔ ﺗﻌﻨﻲ‬ ‫اﻟﺸﺮﻳﻂ أو اﻟﻠﻔﺎﻓﺔ‬ Definition: It is the sheet of connective tissue that lies under the skin as well as between the muscles and internal organs....

Basis of Human Anatomy Dr Hossam Yahia 2nd Lecture Fascia In Latin words, fascia means “band” ‫ﻓﻲ اﻟﻠﻐﺔ اﻟﻌﺮﺑﻴﺔ ﺗﻌﻨﻲ‬ ‫اﻟﺸﺮﻳﻂ أو اﻟﻠﻔﺎﻓﺔ‬ Definition: It is the sheet of connective tissue that lies under the skin as well as between the muscles and internal organs. Classification: Superficial fascia Deep fascia Internal fascia  Muscles Deep fascia Superficial fascia Skin Fascia of Arm and Forearm  Superficial Fascia & Deep Fascia Superficial fascia Muscle Deep fascia Skin Extensor digitorum longus Superficial peroneal nerve muscle  1) Superficial Fascia A) Structure: - It is a layer of loose CT that lies just deep to the skin - It contains a variable quantity of fat, more in females - Its fat is abundant in the breast, anterior abdominal wall and gluteal region - Its fat is absent in the eyelids, ear, penis and scrotum B) Functions of the superficial fascia: 1) Softens and smoothens surface of the body 2) Facilitates movement of skin over the underlying structures 3) Medium to conduct nerves, blood vessels and lymphatics to the skin 4) Prevents heat loss from the body (thermal insulator) 5) Contains cutaneous muscles, as in the face (muscles of expression), neck (platysma muscle), scrotum (Dartos muscle) and hand (palmaris brevis muscle) 6) Contains special types of glands as mammary glands and superficial lymph nodes 7) Shock absorption at sites of pressure as sole of foot and palm of hand Superficial fascia softens and smoothens surface of the body Superficial fascia is a medium for passage of blood vessels and nerves Mammary Gland in the Superficial Fascia of the Breast  Mammary Gland in the Superficial Fascia of the Breast [N.B.] The gland lies within the fat and has no fibrous capsule, so breast cancer invades early and easily the surrounding structures e.g. skin and muscles Platysma Muscle in the Skin of the Neck Dartos Muscle in the Skin of the Scrotum Dartos muscle Dartos muscle in the scrotum is an involuntary muscle that replaces the fat of the superficial fascia. It plays an important role in thermoregulation of the testis  2) Deep Fascia A) Structure: - It is a non-elastic white tough membrane, formed of compact and regular collagen fibers - It is well-defined in the limbs, and is very thick and strong in the palm and sole - It is absent in the face and in the anterior abdominal wall Absence of deep fascia in the face allows muscles to insert directly into the skin and produce movements of facial expression B) Functions: 1) Formation of broad sheets; Around groups of muscles To give muscle attachment To fix underlying structures To help venous return (circulation) 2) Formation of intermuscular septa; to separate different muscle groups having different action and nerve supply 3) Formation of interosseous membranes; to increase the surface area for muscle attachment 4) Formation of retinacula; Localized transverse bands around the wrist and ankle joints to keep the tendons in position 5) Formation of palmar aponeurosis and plantar aponeurosis; very thick and strong layers of deep fascia to protect underlying nerves, vessels and tendons 6) Formation of fibrous sheaths around the big vessels; Like carotid sheath in the neck around common carotid artery, internal jugular vein and vagus nerve Carotid sheath Carotid sheath 7) Formation of fibrous sheaths around the flexor tendons of hands and feet; 8) Formation of fibrous pulleys; under which a muscle tendon can pass e.g. digastric muscle 9) Formation of fibrous raphe; a fibrous band that receives the insertion of 2 muscles e.g. mylohyoid raphe  3) Internal Fascia A) Structure: CT lining body cavities and extending between the different organs B) Function: 1) Forms strong coats around organs e.g. fibrous pericardium 2) Forms supporting ligaments for certain organs 3) Fixes internal organs in position