• Skull 
  Cranium
  o    Superior portion formed by the frontal. parietal, and occipital bones
  o    Lateral portions formed by the temporal and sphenoid bones
  o    Cranial base formed by the temporal. sphenoid, and ethmoid bones
  o    Fontanels-soft spots in which ossification is incomplete at birth

  Frontal bone
  o    Forms the forehead
  o    Contains the frontal sinuses
  o    Forms the roof of the orbits
  o    Union with the parietal bones forms the coronal suture

  Parietal bones
  o    Union with the occipital bone forms the lambdoid suture
  o    Union with the temporal bone forms the squamous suture
  o    Union with the sphenoid bone forms the coronal suture

  Temporal bones
  o    Contains the external auditory meatus and middle and inner ear structures
  o    Squamous portion-above the meatus: zygomatic process-articulates with the zygoma
  o    to form the zygomatic arch 

  •    Petrous portion
  o    Contains organs of hearing and equilibrium 
  o    Prominent elevation on the floor of the cranium

  •    Mastoid portion
  o    Protuberance behind the ear

  o    Mastoid process
  •    Glenoid fossa-articulates with the condyle on the mandible
  •    Styloid process-anterior to the mastoid process; several neck muscles attach here
  •    Stylomastoid foramen-located between the styloid and mastoid processes; facial nerve emerges through this opening
  •    Jugular foramen-located between the petrous portion and the occipital bone: cranial nerves IX. X, and XI exit
   

Nerves of the Face

Innervation of the Muscles of Facial Expression

The Facial Nerve (CN VII)

• The seventh cranial nerve supplies the superficial muscle of the neck (platysma), the muscles of facial expression, the auricular muscles and the scalp muscles.
• CN VII is the sole motor supply to the muscles of facial expression.

• The facial nerve emerges from the skull though the stylomastoid foramen.
• Almost immediately, it enters the parotid gland. It runs superficially in this gland before giving rise to its five terminal branches: temporal, zygomatic, buccal, marginal mandibular, and cervical.
• These nerve emerge from the superior, anterior and inferior margins of the gland and spread out like the abducted digits of the hand to supply the muscles of facial expression.

• The temporal branches of CN VII cross the zygomatic arch to supply all the superficial facial muscles superior to it, including the orbital and forehead muscles.

• The zygomatic branch of CN VII passes transversely over the zygomatic bone to supply the muscles in the zygomatic, orbital and infraorbital regions.

• The buccal branches of CN VII pass horizontally, external to the masseter muscle, to supply the buccinator and the muscles of the upper lip.

• The marginal mandibular branch of CN VII supplies the muscles of the lower lip and chin.

• The cervical branch of CN VII supplies the platysma and the superficial muscles of the neck.

-> This is a wedge-shaped bone (G. sphen, wedge) is located anteriorly to the temporal bones.
-> It is a key bone in the cranium because it articulates with eight bones (frontal, parietal, temporal, occipital, vomer, zygomatic, palatine, and ethmoid).
-> It main parts are the body and the greater and lesser wings, which spread laterally from the body.
-> The superior surface of its body is shaped like a Turkish saddle (L. sella, a saddle); hence its name sella turcica.
-> It forms the hypophyseal fossa which contains the hypophysis cerebri or pituitary gland.
-> The sella turcica is bounded posteriorly by the dorsum sellae, a square plate of bone that projects superiorly and has a posterior clinoid process on each side.
-> Inside the body of the sphenoid bone, there are right and left sphenoid sinuses. The floor of the sella turcica forms the roof of these paranasal sinuses.
-> Studies of the sella turcica and hypophyseal fossa in radiographs or by other imaging techniques are important because they may reflect pathological changes such as a pituitary tumour or an aneurysm of the internal carotid artery. Decalcification of the dorsum sellae is one of the signs of a generalised increase in intracranial pressure.

The Inferior Wall of the Orbit

• The thin inferior wall of the orbit or the floor is formed mainly by the orbital surface of the maxilla and partly by the zygomatic bone, and orbital process of the palatine bone.

• The floor of the orbit forms the roof of the maxillary sinus.

• The floor is partly separated from the lateral wall of the orbit by the inferior orbital fissure.

Appendicular Skeleton
Upper extremity
•    Shoulder-clavicle and scapula

Clavicle
    Articulates with the manubrium at the sternal end
    Articulates with the scapula at the lateral end
    Slender S-shaped bone that extends horizontally across the upper part of the thorax
    
Scapula

    Triangular bone with the base upward and the apex downward
    Lateral aspect contains the glenoid cavity that articulates with the head of the humerus
    Spine extends across the upper part of the posterior surface; expands laterally and
    forms the acromion (forms point of shoulder) 
    Coracoid process projects anteriorly from the upper part of the neck of the scapula
    
Arm (humerus)

Consists of a shaft (diaphysis) and two ends (epiphyses)
Proximal end has a head that articulates with the glenoid fossa of the scapula
Greater and lesser tubercles lie below the head

Intertubercular groove is located between them; long tendon of the biceps attaches here
Surgical neck is located below the tubercles

    o    Radial groove runs obliquely on the posterior surface; radial nerve is located here

    o    Deltoid muscles attaches in a V-shaped area in the middle of the shaft. called the deltoid tuberosity
    
Distal end has two projections. the medial and lateral epicondyles
Capitulum-articulates with the radius
Trochlea-articulates with the ulqa

Forearm

Radius
Lateral bone of the forearm
Radial tuberosity is located below the head on the medial side
Distal end is broad for articulation with the wrist: has a styloid process on its lateral side

Ulna

    Medial side of the forearm
    Conspicuous part of the elbow joint (olecranon)
    Curved surface that articulates with the trochlea of the humerus is the trochlearnotch
    Lateral ide is concave (radial notch); articulates with the head of the radius Distal end contains the styloid process 
    Distal end contains the styloid process

Hand

Carpal bones (8)
    Aranged in two rows of four
    Scaphoid. lunate. triquetral. and pisiform  proximal row); trapezium. trapezoid.
    capitate. and hamate (distal row)
    
Metacarpal bones (5)
    Framework of the hand
    Numbered 1 to 5 beginning on the lateral side
    
Phalanges (14)
    Fingers
     Three phalanges in each finger; two phalanges in the thumb

The Scalp

• The scalp consists of five layers of soft tissue.
• It extends from the superior nuchal line on the posterior aspect of the skull of the supraorbital margins.
• Laterally, the scalp extends into the temporal fossa to the level of the zygomatic arches.

Layers of the Scalp

• The scalp proper is composed of three fused layers. It is separated from the pericranium by loose connective tissue.
• Because of this potential areolar cleavage plane, the scalp is fairly mobile.
• Each letter of the word "S C A L P" serves as a memory key for one of the layers of the scalp: Skin, Connective Tissue, Aponeurosis Epicranialis, Loose Areolar Tissue and Pericranium.

Layer 1: Skin

• Hair covers the scalp in most people.
• The skin of the scalp is thin, especially in elderly people, except in the occipital region.
• The skin contains many sweat and sebaceous glands and hair follicles.
• The skin of the scalp has an abundant arterial supply and good venous and lymphatic drainage systems.

Layer 2: Connective Tissue

• This is a thick, subcutaneous layer of connective tissue and is richly vascularised and innervated.
• It attaches the skin to the third layer of the scalp.
• Fat is enclosed in lobules between the connective fibres.

Layer 3: Aponeurosis Epicranialis

• This is a strong membranous sheet that covers the superior aspect of the cranium.
• This aponeurosis is the membranous tendon of the fleshy bellies of the epicranius muscle.

• The epicranius muscle consists of four parts: two occipital bellies, occipitalis and two frontal bellies, frontalis that are connected by the epicranial aponeurosis. 

Layer 4: Loose Areolar Tissue

• This is a subaponeurotic layer or areolar or loose connective tissue.
• It is somewhat like a sponge because it contains innumerable potential spaces that are capable of being distended by fluid.
• It is this layer that allows free movement of the scalp proper, composed of layers 1-3.

Layer 5: Pericranium

• This is a dense layer of specialised connective tissue.
• The pericranium is firmly attached to the bones by connective tissue fibres called Sharpey’s fibres, however, they can be fairly easily stripped from the cranial bones of living persons, except where they are continuous with the fibrous tissues of the cranial sutures.