pediagenosis: HeadNeck
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Showing posts with label HeadNeck. Show all posts
Showing posts with label HeadNeck. Show all posts

Tuesday, April 6, 2021

Proprioception And Reflexes

Proprioception And Reflexes

Proprioception And Reflexes
We are aware of the orientation of our limbs with respect to one another, we can perceive the movements of our joints and we can accurately assess the amount of resistance (force) that opposes the movements we make. This ability is called proprioception. The three qualities of this modality are position, movement and force. The receptors or proprioceptors that mediate this modality are principally found in the joint capsules (joint receptors), muscles (muscle spindles) and tendons (Golgi tendon organs).
The joint capsule is compressed or stretched when the joint moves, and mechanoreceptors within it signal the position of the joint, as well as the direction and velocity of the movement. Individual receptors respond to the position of the joint, as well as the direction and the velocity of the movement, but not the force. The receptor types found in the joint capsule are Ruffini-type (slowly adapting) stretch receptors (Chapter 55).
Proprioception And Reflexes

Each muscle contains a number of small muscle fibres (intrafusal muscle fibres: 15–30 μm in diameter and 4–7 mm in length) that are thinner and shorter than the ordinary muscle fibre (extrafusal muscle fibres: 50–100 μm in diameter and varying in length from a few millimetres to many centimetres). Several intrafusal fibres are grouped together and encased in a connective tissue capsule, called the muscle spindle, a specialized receptor that responds to the stretch of a muscle (Fig. 60a). Muscle spindles lie in parallel to the extrafusal muscle fibres and are elongated when the muscle is stretched. The primary sensory innervation of the muscle spindle consists of afferent fibres which wind themselves around the centre of the intrafusal muscle fibres (annulospiral ending). These are large myelinated fibres (group Ia afferents). These endings are called primary sensory endings and, when excited, they evoke a monosynaptic stretch reflex involving an excitation of the homonymous α-motor neurones and reciprocal inhibition of the heteronymous α-motor neurones (Fig. 60b).

Thursday, October 22, 2020

Superficial Arteries and Veins of Face and Scalp Anatomy

Superficial Arteries and Veins of Face and Scalp Anatomy

Superficial Arteries and Veins of Face and Scalp Anatomy 
Middle temporal artery and vein, Zygomaticoorbital artery, Transverse facial artery and vein, Supraorbital artery and vein, Supratrochlear artery and vein, Nasofrontal vein, Facial artery and vein, External nasal artery and vein, Zygomaticotemporal artery and vein, Angular artery and vein, Zygomaticofacial artery and vein
Skull: Anterior View Anatomy

Skull: Anterior View Anatomy

Skull: Anterior View Anatomy
Frontal bone : Glabella, Supraorbital notch (foramen), Orbital surface. Nasal bone, Lacrimal bone, Zygomatic bone : Frontal process, Orbital surface, Temporal process, Zygomaticofacial, foramen. Maxillary bone ( Zygomatic process, Orbital surface, Frontal process, Infraorbital foramen, Alveolar process, Anterior nasal spine). Coronal suture.
Skull: Radiographs Anatomy

Skull: Radiographs Anatomy

Skull: Radiographs Anatomy
Posterior anterior view ( Sagittal suture, Lesser wing of sphenoid bone, Petrous part of temporal bone, Mastoid cells, Nasal septum, Dens (C2), Body of axis, Coronal suture, Lambdoid suture, Frontal sinus, Superior orbital fissure, Foramen rotundum, Maxillary sinus, Inferior nasal concha).
Skull: Lateral View Anatomy

Skull: Lateral View Anatomy

Skull: Lateral View Anatomy
Sphenoid bone Greater wing, Frontal bone ( Supraorbital notch (foramen), Glabella), Ethmoid bone Orbital plate, Lacrimal bone Fossa for lacrimal sac, Nasal bone, Maxillary bone ( Frontal process, Infraorbital foramen, Anterior nasal spine, Alveolar process), Temporal bone ( Squamous part, Zygomatic process, Articular tubercle, Groove for posterior deep temporal artery, Supramastoid crest, External acoustic meatus, Mastoid process, Lambdoid suture), Occipital bone, Sutural (wormian) bone, External occipital protuberance (inion), Asterio.
Head and Neck: Surface Anatomy

Head and Neck: Surface Anatomy

Head and Neck: Surface Anatomy
Frontal bone, Supraorbital notch, Superciliary arch, Glabella, Nasal bone, Anterior nares (nostril), Philtrum, Nasolabial sulcus, Tubercle of upper lip, Mental protuberance, Thyroid cartilage, Jugular notch, Sternal head of sternocleidomastoid muscle,

Tuesday, October 13, 2020

Masseter, Temporalis and Infratemporal Fossa

Masseter, Temporalis and Infratemporal Fossa


Masseter, Temporalis and Infratemporal Fossa
Masseter
Masseter (Fig. 7.29) attaches along the length of the zygomatic arch and its fibres slope downwards and backwards to the lateral surface of the ramus of the mandible adjacent to the angle (Fig. 7.31). This muscle is a powerful elevator of the mandible and is easily palpated when the teeth are clenched. It is supplied by the masseteric branch of the mandibular (V3) division of the trigeminal nerve.
Digastric and Styloid Muscles

Digastric and Styloid Muscles


Digastric and Styloid Muscles
Digastric
The digastric muscle (Fig. 7.35) consists of anterior and posterior bellies united by an intermediate tendon. The posterior belly attaches to the medial surface of the mastoid process and inclines forwards and downwards, becoming continuous with the intermediate tendon close to the hyoid bone. This tendon pierces stylohyoid and is anchored by a fascial sling to the hyoid bone. The anterior belly continues forwards from the intermediate tendon to attach to the inferior border of the mandible near the midline. Digastric elevates the hyoid bone during swallowing and assists mylohyoid and the lateral pterygoid in depressing the mandible when opening the mouth. The posterior belly is innervated by the facial (VII) nerve (p. 340). The anterior belly receives its motor supply from the mandibular (V3) division of the trigeminal nerve via the mylohyoid branch of the inferior alveolar nerve (p. 345).
Mylohyoid and Related Structures

Mylohyoid and Related Structures


Mylohyoid and Related Structures
Suspended from the body of the mandible is a thin sheet of muscle formed by the two mylohyoid muscles. The fibres of each muscle incline downwards and medially, meeting each other in the midline to form a shallow gutter. This gutter slopes downwards and backwards and ends at the free posterior borders of the two muscles on either side of the hyoid bone.
Larynx Anatomy

Larynx Anatomy


Larynx Anatomy
The larynx acts as a sphincter guarding the lower respiratory tract and is responsible for phonation. It lies in the neck and its inlet is continuous with the laryngopharynx (Figs 7.61 & 7.62). Inferiorly, the larynx is continuous with the trachea. It consists of a framework of cartilages and bone, which supports the vocal and vestibular folds and the muscles that move them. Anteriorly lie the infrahyoid strap muscles.
Pharynx Anatomy

Pharynx Anatomy


Pharynx Anatomy
The pharynx is a muscular tube, which is continuous inferiorly with the oesophagus and into which the nasal, oral and laryngeal cavities open (Fig. 7.60). For descriptive purposes, the pharynx is divided into nasopharynx, oropharynx and laryngopharynx (hypopharynx Fig. 7.55). The nasopharynx is attached to the base of the skull and is bounded anteriorly by the choanae. Inferiorly, it is continuous with the oropharynx at the level of the soft palate. The oropharynx begins anteriorly at the palatoglossal ridge and extends inferiorly to the level of the upper border of the epiglottis, where it is in continuity with the laryngopharynx. The laryngopharynx lies behind the laryngeal inlet, the arytenoids and the cricoid lamina, and on either side of the inlet forms recesses, the piriform fossae (Fig. 7.61). In normal deglutition, these fossae are traversed by fluid and food which pass behind the cricoid cartilage in the terminal part of the laryngopharynx. Foreign bodies such as fish bones may lodge in these recesses during swallowing. At the inferior border of the cricoid cartilage, it is continuous with the oesophagus. The musculature of the pharynx consists of incomplete outer circular and inner longitudinal layers. The pharyngobasilar fascia lies internal to the muscle coat and is lined by mucous membrane.

Saturday, September 19, 2020

 What Does The Spinal Cord Do?

What Does The Spinal Cord Do?

 What Does The Spinal Cord Do?

The spinal cord actually is part of the brain and plays a major role. Scientists have known for the past 100 years or so that the spinal cord is actually part of the brain. According to Melillo, while the brain has grey matter on the outside (protected by the skull) and protected white matter on the inside, the spinal cord is the reverse: the grey matter is inside the spinal cord and the white matter is outside.

How Do Nerves Work?

How Do Nerves Work?

How Do Nerves Work?

Nerves carry signals throughout the body – a chemical superhighway, Nerves are the transmission cables that carry brain waves in the human body, says Sol Diamond, an assistant professor at the Thayer School of Engineering at Dartmouth. According to Diamond, nerves communicate these signals from one point to another, whether from your toenail up to your brain or from the side of your head.

Neurons Explained

Neurons Explained

Neurons Explained

Neurons fire like electrical circuits. Neurons are a kind of cell in the brain (humans have many cells in the body, including fat cells, kidney cells, and gland cells). A neuron is essentially like a hub that works with nearby neurons to generate an electrical and chemical charge. Dr Likosky of the Swedish Medical Institute says another way of thinking about neurons is that they are like a basketball and the connections (called axons) are like electrical wires that connect to other neurons. This creates a kind of circuit in the human body. Tallal explained that input from the five senses in the body cause neurons to fire.

Monday, September 14, 2020

Functions of The Cerebral Cortex

Functions of The Cerebral Cortex


Functions of The Cerebral Cortex
The cerebral cortex is the wrinkling part of our brain that shows up when you see pictures of the brainThe outside world and making sense of it. The brain is actually a series of interconnected ‘superhighways’ or pathways that move ‘data’ from one part of the body to another.
Your Brain Anatomy

Your Brain Anatomy


Your brain Anatomy
It’s a computer, a thinking machine, a pink organ, and a vast collection of neurons – but how does it work? The human brain is amazingly complex – in fact, more complex than anything in the known universe. The brain effortlessly consumes power, stores memories, processes thoughts, and reacts to danger.

Saturday, May 2, 2020

Orbit Anatomy

Orbit Anatomy


Orbit Anatomy
The orbit is a pyramidal cavity, the apex of which is directed posteriorly and base anteriorly (Fig. 7.83). Its bony walls separate it from the anterior cranial fossa above, the ethmoidal air cells and nasal cavity medially, the maxillary air sinus inferiorly and the lateral surface of the face and temporal fossa laterally (Fig. 7.84). Anteriorly, the orbit presents a roughly rectangular aperture which is closed by the eyelids. Within the orbit are the eyeball, the extraocular muscles, cranial nerves II, III, IV, V (ophthalmic and maxillary divisions) and VI, and blood vessels, lymphatics and fat.

Tuesday, April 28, 2020

Cranium and Contents Anatomy

Cranium and Contents Anatomy


Cranium and Contents Anatomy
The part of the skull that contains the brain and its immediate relations is called the neurocranium. Although the detailed anatomy of the central nervous system is outside the scope of this book, there are some important surface features of the brain (Figs 7.73 & 7.74) to which reference should be made when considering the bony features of the interior of the cranium.

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